ICU acquired pneumonia due to pseudomonas aeruginosa with and without multidrug resistance

Objectives: To assess risk factors for ICU-acquired pneumonia (ICUAP) caused by P. aeruginosa with and without multidrug resistance (MDR). Methods: We prospectively collected 394 consecutive episodes of ICUAP. We compared characteristics, severity and outcomes between cases caused by P. aeruginosa and other pathogens, and between P. aeruginosa with and without MDR. Results : 246 (62%) cases had etiologic diagnosis. P. aeruginosa was the most frequent pathogen (72, 29%), 21 (29%) cases had MDR. Patients with P. aeruginosa were older, more often previously colonized by P. aeruginosa, had received more frequently previous antibiotics, had higher rates of chronic obstructive pulmonary disease, less frequent alcohol abuse and less pleural effusion. Prior airway colonization by P. aeruginosa and previous antibiotics independently predicted P. aeruginosa aetiology, while alcohol abuse and pleural effusion were associated to a lower risk for this pathogen. Patients with MDR P. aeruginosa had lower levels of C-reactive protein at day 3 and interleukin-6 at day 1 than those with P. aeruginosa without MDR. Non-response to treatment and 90-day mortality was not significantly different between cases with and without P. aeruginosa, even adjusting for confounders, as well as in patients with P. aeruginosa with and without MDR. Conclusion: Prior colonization by P. aeruginosa and antimicrobial treatment independently predicted P. aeruginosa aetiology, while alcohol abuse and pleural effusion were associated to a lower risk for this pathogen. P. aeruginosa is not associated to higher mortality or treatment failure compared to other pathogens. Support: Ciberes (CB06/06/0028), 2009 SGR 911, ERS Fellowship, IDIBAPS.